Moveable Median Barrier Project

Successful Installation

The Golden Gate Bridge became safer for drivers after the weekend of January 10, 2015, when the Golden Gate Bridge, Highway and Transportation District installed a new Moveable Median Barrier (MMB) to virtually eliminate the possibility of a head-on collision. The solid, semi-rigid Barrier is made up of 3,517 interlocking steel and concrete units, each weighing 1500 pounds and standing 32 inches tall. It replaces the yellow plastic pylons that had visually separated northbound and southbound traffic ever since lane management began in the early 1960’s. Read the whole Press Release here.

Moveable Median Barrier Project & Budget

The Moveable Median Barrier (MMB) system includes about 13,340 feet of barrier consisting of 12-inch wide and 32-inch high steel clad units filled with high density concrete tightly pinned together to form a semi-rigid median barrier. The system also includes two barrier transfer machines, aka “zipper” trucks. The installation of the one-foot wide MMB would virtually eliminate crossover collisions.

The project budget is estimated at $30.3 million with funding coming from three sources: $20 million (66%) from the Metropolitan Transportation Commission via the State of California; $1,379,200 (5%) in federal funds; and $5,120,800 (19%) from Golden Gate Bridge toll revenues.

2012 Final Design

On October 26, 2012, the Board of Directors approved proceeding with the final design and preparation of the construction bid documents for installation of a Moveable Median Barrier. The Board also authorized the filing of a Notice of Exemption based upon the environmental studies finding the project to be exempt from the requirements of the California Environmental Quality Act. The resulting reports are available below:

Roadway Condition, post Roadway Deck Replacement (1984)

Since 1984, total annual traffic crossing, including both northbound and southbound, at the Golden Gate Bridge has been between 38 million to 42 million vehicles. The roadway is 1.7 miles long with six lanes that include two, 11-foot wide curb lanes (widened by 1 foot during the roadway deck replacement) and four 10-foot wide lanes. Opposing directions of traffic are separated by 19-inch tall, 4-inch diameter plastic tubes, spaced at 25-foot intervals. These tubes are manually placed in sockets in the roadway to identify the San Francisco outbound (northbound) lanes and San Francisco inbound (southbound) lanes and are reconfigured several times per day based on real time traffic.

Project Timeline - 1996 to present

July 9-13, 2015: The moveable median barrier was extended about 900 feet south of the Bridge Toll Plaza to conform to the new Doyle Drive concrete median barrier at the District's property line.

November 2014: Construction continues. An 800-foot section of concrete barrier on the north approach to the Bridge is removed and the roadway median in that area is repaved.

August 2014: Construction begins with the removal of the 8-foot Art Deco clock and Toll Plaza modifications, including removal of 4 toll booths (lanes 8 to 11) and the reconstruction of a new toll booth (lane 8).

July to December 2014: Toll Plaza refurbishment and nighttime lane closures in preparation for MMB installation. Read the Press Release here.

October 26, 2012: The Board of Directors approve proceeding with the final design and preparation of the construction bid documents for installation of a Moveable Median Barrier on the Golden Gate Bridge, based on the findings of technical studies conducted during the project environmental and preliminary design stage which concluded that the installation of the barrier is feasible and warranted by criteria established Caltrans.

August 16, 22, and 28, 2012: District staff met with Caltrans to review Caltrans’ comments and modifications to the Traffic Report in response to Caltrans’ comments. Caltrans provided additional comments on September 10, 2012.

July 16 and July 31, 2012: District staff met with Caltrans and reviewed the outstanding comments on the Traffic Study, Geometric Design and Design Exceptions. Caltrans requested additional information regarding the traffic operations within Caltrans’ right-of-way north of the Bridge north abutment. The District has submitted the requested information to Caltrans for review.

June 14, 2012: Cooperative Agreement referenced under May 24, 2012 was executed with Caltrans.

May 24, 2012: The Board of Directors authorized the General Manager to execute a Cooperative Agreement with Caltrans that outlines the coordination of responsibilities for environmental evaluation, design and construction of the portion of the Golden Gate Bridge moveable median barrier to be installed within the State Highway 101 right-of-way north and south of the Golden Gate Bridge.

April 6, 2012: District staff received Caltrans’ written comments on the revised Traffic Study and Design Exceptions fact sheet noted below under January 17, 2012 and responded to the comments. District is waiting for Caltrans’ comments. Staff has reviewed the 35% completion design plans and proposed changes to the lane striping. The consultant evaluated the impact of the proposed change on traffic operations and determined that traffic operations will be improved.

February 14, 2012: District staff met with Caltrans on to review the changes submitted in January.

October 26, 2011, November 3, 2011, and December 1, 2011: District staff met with Caltrans to discuss reports. Caltrans has approved all of the reports except for the Traffic Study.

March 15, 2011: Staff met with the consultants to discuss issues regarding the Draft Environmental and Technical Studies required for the Moveable Median Barrier project. The consultant has submitted to Caltrans for review and approval the preliminary cost estimate, the proposed geometric alignment modifications, the Natural Environment Study [Minimal Impacts] (NESMI) Report, the Visual Impact Assessment Report (VIAR), the Traffic Engineering and Analysis Report (Traffic Study), the Cultural Resources (Section 106 Finding of Effect [FOE]) Report and the Section 4(f) Report. Section 4(f) of the Department of Transportation Act of 1966 requires that an evaluation must be made to determine if a proposed project will cause any impacts to any significant publicly owned public park, recreation area, or wildlife and waterfowl refuge, and any land from an historic site of national, state, or local significance.

February 1, 2010: District staff met with Caltrans to review the appropriate type of environmental document needed for the project and to perform a site review.

2009: The work for the Environmental Studies and Preliminary Design for a MMB on the Golden Gate Bridge began. The consultant developed conceptual designs regarding how the moveable median barrier would safely transition and terminate (from a traffic operations perspective) on the Waldo Grade and at the south end of the Bridge. The consultant prepared and submitted the required Preliminary Environmental Studies form to Caltrans.

September 12, 2008: The Board of Directors approved a Professional Services Agreement for Environmental Studies and Preliminary Design for a MMB on the Golden Gate Bridge to AECOM, USA, Inc. (formerly DMJM Harris), to perform preliminary engineering and environmental studies.

June 2008: A Request for Proposals was issued to solicit consultants to work with the District to complete the legally required detailed design and environmental studies - Environmental Studies and Preliminary Design for a MMB on the Golden Gate Bridge. The scope of the services generally consisted of: Preparing environmental studies pursuant to state and federal requirements; Developing preliminary design and cost estimates for the MMB system, including facilities to store and maintain the barrier transfer machines; Exploring, developing, evaluating and reviewing, from a traffic operations and environmental perspective, potential design variations for a MMB on the Bridge.

Late 2007 to early 2008: The required Wind Tunnel Testing was conducted on the Moveable Median Barrier. When any modification is contemplated for the Golden Gate Bridge, it is essential that they are tested for wind stability to ensure that there is no negative impact to the wind dynamics of the span. Wind tunnel testing was done on the MMB in conjunction with three generic design concepts for a suicide barrier on the span. It has been determined that a MMB can be added safely to the Bridge without negatively impacting the wind stability of the Bridge.

January 2007: Bridge roadway is established as a Safety Awareness Zone.

January 2002: Parsons Brinckerhoff reported their findings in Movable Median Barrier Feasibility Studies—Phase II and provided the following conclusions: (1) Placing a MMB on the Bridge will result in decreased lane widths in at least two lanes at any one time. While there is no “perfect” lane configuration, there are several potentially viable lane configurations, each of which, however, has certain drawbacks, (2) Installation of a MMB on the Bridge could theoretically result in a reduction in capacity in the two- and three-lane configurations, but it is also possible that this capacity reduction may not occur. The ultimate result is not certain, (3) Installation of a MMB on the Bridge would result in a virtual elimination of crossover head-on accidents. Head-on fatal accidents occur less frequently than other types of accidents; but this type of accident causes significantly greater delays per accident, (4) Installation of a MMB would result in certain other types of accidents (e.g. rear enders in the two lane direction) being more difficult to clear due to the presence of the barrier, resulting in longer delays than the current condition for these accident types. It is assumed that the introduction of a MMB on the Bridge will not result in a change in the overall accident rate, but this is not certain, (5) The elimination of delays associated with crossover accidents might be offset by the increase in delays caused by non-crossover accidents. Over the course of a year, as opposed to a per incident basis, overall delays associated with accidents may not significantly change, but again this cannot be predicted with certainty. The Phase I and Phase II studies performed by Parsons Brinckerhoff did not address all of the technical and operational issues identified previously in Resolution 98-116 authorized by the Board of Directors on May 22, 1998. However, of the issues that were studied, none categorically ruled out installation of a MMB on the Bridge, but as reported in the findings, the possible resolution of those issues involved balancing of pros and cons and acceptance of trade-offs. To address the remaining technical and operational issues outlined in the May 22, 1998 Resolution 98-116, and to answer many of the final operational, engineering and cost details, it is necessary to proceed with detailed design and environmental studies.

March 9, 2001: By Resolution 2001-044, the Board of Directors accepted Parsons Brinckerhoff‘s findings and authorized Parsons Brinckerhoff to conduct Phase II studies: (1) Evaluate the traffic congestion impact of decreasing lane widths on the Bridge with the MMB installed, and (2) Evaluate the impact of the MMB on traffic congestion associated with traffic accidents and stalls on the Bridge.

August 1999: The Board of Directors authorized the first of several studies of some of these unresolved technical and operational issues as part of a preliminary engineering evaluation and, by Resolution 99-175, authorized Parsons Brinckerhoff (PB), San Francisco, CA, to perform the following services, as Phase I, relative to the possible installation of a MMB: (1) Evaluate MMB end treatment and anchorage schemes at the toll plaza, (2) Evaluate storage requirements for the Barrier Transfer Machine (BTM) at the north end, (3) Evaluate strategies for delineation of traffic lanes on the Bridge with a MMB installed, (4) Develop emergency response procedures for accidents or incidents that require emergency response across or through a MMB. Parsons Brinckerhoff’s findings were presented in two reports: (1) Conceptual Engineering Design Studies and, (2) Emergency Operations Report. Parsons Brinckerhoff concluded that possible engineering solutions may exist for those aspects of a MMB installation that were studied, subject to further design and development during a future detailed engineering design phase, provided that the Board accept the various trade-offs involved in those proposed solutions. Parsons Brinckerhoff also concluded that existing emergency response procedures would have to be modified and/or supplemented to provide satisfactory emergency response with a MMB present, again with the recognition that such procedures may have certain drawbacks and involve certain trade-offs.

May 22, 1998: The Board of Directors, by Resolution 98-116, authorized a conceptual approval for the installation of the Barrier Systems Incorporated one foot wide MMB on the Bridge and authorized staff to investigate acceptable solutions to the many remaining technical and operational items (approximately 28 different items) that must be resolved prior to installation. Additionally, the Board directed staff to develop a cost estimate for the MMB installation, identify necessary permits, and to begin to identify possible funding sources. A phased approach would be implemented to resolve the many remaining technical and operational issues identified as part of the May 1998 conceptual approval process.

January 16, 1998. The Board of Directors receives an informational status report on the Moveable Median Barrier.

December 1997: Professor Robert K. Seyfried, Northwestern, presented the findings of the October 29, 1997, report to the Building and Operating Committee of the Board of Directors. Professor Seyfried explained that the report concluded that the decision is a virtual toss-up, and the Board could reasonably make a decision either way—install a MMB or forgo installation of a MMB. The Board’s final decision must result from a balancing of factors and considerations, which in turn would require the Board to determine which considerations and factors, are most important

May 1, 1997: A draft report on the crash testing was submitted by E-Tech.

March 1997: Crash testing took place on the one-foot-wide moveable median barrier developed by Barrier Systems. An independent testing agent, E-Tech Testing Services Incorporated, Lincoln, California performed crash testing of Barrier System Incorporated’s one-foot barrier pursuant to the National Cooperative Highway Research Program Report No. 350. The District contributed $32,450 towards the testing. Crash testing was conducted with a car weighing 1,800 pounds and a pickup truck weighing 4,400 pounds. Both vehicles hit the barrier at a speed of 62 miles per hour. The car hit the barrier at an approach angle of 20 degrees, while the truck hit it at angle of 25 degrees. The barrier structure itself performed well in both crashes.

September 1996: The Board of Directors authorized a Traffic Engineering and Safety Analysis to be conducted by Northwestern.

September 1996: The Golden Gate Bridge was temporality named a Double Fine Zone.

July 12, 1996: The Board of Directors, by Resolution 96-163, authorized the District’s financial participation, in the amount of $42,500, in the crash test of the new Barrier Systems Incorporated one foot wide MMB. The Board also authorized engaging services of The Traffic Institute of Northwestern University (Northwestern) to evaluate various traffic and safety ramifications of the installation of the new one foot wide MMB on the Bridge.

1995: Barrier Systems Incorporated informs the District that they have developed the prototype for one-foot wide MMB.

1985: After extensive study, the Board of Directors rejects a 2-foot wide MMB as not feasible for use on the Golden Gate Bridge.